Signal detector of magnetic disk apparatus

Abstract

A signal detector of a magnetic disk apparatus has a comparator for generating a pulse signal when an analog signal from a magnetic head for performing the read/write operation of data falls within a range between predetermined voltage levels, a flip-flop for receiving an output signal from the comparator and for generating the signal required in converting a peak of the analog signal to a digital signal, in accordance with the output signal from the comparator, and a gate circuit for supplying a clock pulse to the flip-flop, said clock pulse corresponding to the zero-crossing point of the differential signal for detecting the peak of the analog signal and having a predetermined pulse width, in response to the output signal from the comparator.

What is claimed is: 
     
       1. A signal detector for a magnetic disk apparatus having a magnetic head for reading/writing data and a differentiator circuit for differentiating an analog signal produced by said magnetic head, comprising: zero crossing means, coupled to said differentiator circuit, for detecting the zero-crossing point of the output of said differentiator circuit;   peak detecting means, coupled to said differentiator circuit, for generating a signal representing the peaks of the output signal from said magnetic head;   gate enable signal generating means, coupled to said output from said magnetic head, for generating a signal enabling said zero crossing means to supply an output to said peak detecting means based on said output signal from said magnetic head; and   gate disable signal generating means for prohibiting the output from said zero crossing means from being supplied to said data generating means, based on the output from said gate enable signal generating means and the output from said means;   said peak detecting means being coupled to said zero detecting means, said gate enable signal generating means and said gate disable signal generating means.   
     
     
       2. A detector according to claim 1, wherein said gate enable signal generating means comprises a comparator for generating a pulse signal when the analog signal from said magnetic head falls within a range between predetermined threshold values. 
     
     
       3. A detector according to claim 2, wherein said peak detecting means comprises a gate circuit coupled to said differentiator circuit, said gate circuit being adapted to supply a clock pulse corresponding to the zero-crossing point of the differential signal from said differentiator circuit, said clock pulse having a predetermined pulse width corresponding to an output pulse signal from said comparator. 
     
     
       4. A detector according to claim 3, wherein said gated disable signal generating means comprises a latch circuit coupled to an output from said gate circuit, said latch circuit being adapted to latch the output from said comparator in response to the clock signal from said gate circuit. 
     
     
       5. A signal detector for a magnetic disk apparatus having a magnetic head for accessing a recording medium for data read out/writing, an amplifier circuit for amplifying a reproduced signal from said magnetic head and a low-pass filter circuit for eliminating high-frequency noise, said signal detector capable of detecting a peak of the reproduced signal from said magnetic head, comprising: differentiation circuit means for differentiating said reproduced signal and producing an output signal indicative thereof;   cross-point detecting circuit means for receiving said output signal from said differentiation circuit means and detecting a zero-crossing point of said output signal;   enable signal generating circuit means for receiving said reproduced signal and for generating an output signal based on said reproduced signal to enable a signal detection;   inhibit signal generating circuit means for receiving said output signal of said enable signal generating circuit means and for generating an output signal to inhibit signal detection; and   data detecting circuit means for receiving said output signal of said cross point detecting circuit means, said output signal of said enable signal generating circuit means and said output signal of said inhibit signal generating circuit means, and for performing a logical operation on said inputs of said data detecting circuit means, thereby detecting a signal corresponding to a peak of said reproduced signal.   
     
     
       6. A signal detector for a magnetic disk apparatus having a magnetic head, amplifier and filter which converts the peak position of the read signal of said magnetic disk apparatus to a digital pulse, comprising: differentiation means for differentiating said read signal, thus producing an analog differential signal with zero amplitude when said read signal has a zero slope;   zero detecting means for detecting the zero amplitude occurrences of said differential signal and producing a signal indicative thereof;   comparator means, coupled to said filtered read signal, for assuming two logic states, and for changing logic state when said read signal passes a predetermined threshold;   clockable latch means for latching said logic signal from said comparator means, when said latch is clocked by said indicative signal from said zero detecting means; and   inhibiting means for inhibiting said said latch from being clocked if a peak of said read signal has not occurred.   
     
     
       7. A signal detector as in claim 6 further comprising delay means for delaying said logic states from said comparator means for a predetermined period. 
     
     
       8. A signal detector as in claim 8 wherein said inhibiting means further comprises: gate means for gating said indicative signal from said zero crossing means with a signal representing the validity of said indicative signal.   
     
     
       9. A detector as in claim 8 wherein said latch means is a D-type flip-flop.